Braking apparatus



. y Dec. 8, 1936. w. F. OLIVER BRAKING' APPARATUS Original Filed Deo. 5l, 1931 Patented Dec. 8, 1935 UNITED STATES PATNT 'OFFICE BEARING APPARATUS v Wallace F. Oliver, Detroit, Mich., assignor to Hydraulic Brake Company, Detroit, Mich., a. corporation of California Original application December 31, 1931, Serial No. 584,037. Divided and this application December 2 3, 1932, Serial No. 648,526

paratus is increased withoutan increase in the amount of pedal pressure necessary for effecting application of the brakes.

An object oi my invention, therefore, is to provide a more yeiiicient brake system which will give increased braking effect withoutrequiring the operator to exert increased effort on the operating controls. I

A further object of my invention is the provision of a more emcient braking system in which-forcel multiplying means are utilized for l increasing the pressure'exerted by the operator `on the operating controls in effecting the application of the brakes.

Another object is to provide a braking system I embodying the foregoing features and which may be economically manufactured, has a minimum number of parts, and is durable and absolutely reliable in service.

Other objects and advantages will become apparent as the description proceeds.

I Referring to the drawing, of which one sheet:

Figure 1 isa vertical elevational view, partly in section. and showing my invention applied there is to the wheel brake mechanism of an automobile;

Figure 2 is a horizontal sectional view taken on the line 2-2 of Figure 1 and showing details of the connection between the brake shoe and the force multiplying means.

. I have illustrated my invention as applied to the wheel brake mechanism of an automobile which consists, in general, of a brake drum 'I suitably secured to the vehicle wheel by any well known means, andan axle housing 8 to which is secured a pan 9 which cooperates with the brake drum 1 to'provide an enclosure in which are located the operating parts of the brake mechanism. Supporting pins I are attached to the pan 9 and carry' brake shoes II and I2 which are normally located in the positions shown but which are capable of move- (Cl. 18S-152) ment into engagement with the brake drum 1 by-mechanism which will be generally described hereinafter. The pan 9 also supports guides IIl which guide the brake shoes Il and I2 during their movement between active and inactive position.

A motor cylinder I4 is suitably secured to the pan 9 between the free ends of the brake shoes II and I2. 'I'hismotor cylinder is of uniform bore throughout and is provided with opposedA pistons I and I6 which are operable t0 move the brake shoes II and I2 into braking engagement with the drinn 1 when fluid under pressure is forced into the4 cylinder I4 by sultable fluid compressing means and conduits which may be of the type disclosed in United States patent No. 1,758,671, or which may be of any other suitable orl desirable type.

The piston. i5 is directly connected with ther brake shoe I2 by a piston rod I1 which has one end rounded to t into a socket formed in the rear side of the piston i5 and which forms a separable connection therewith. The other end of the piston rod I1 is provided with a slot I8 intoY which projects the rounded end IQ of the brake shoe I2. The engagement of the end I3 in the slot I8 prevents rotation of the piston rod I1. The speciiic construction of the cylinder and piston is described and claimed in my priorappli-f cation forLetters Patent'on Braking apparatus, led December 3, 193i, Serial No. 584,037, and forms no part of the invention described and claimed in this application which is a division of my said prior application.

When the vehicle is moving in the forward direction the brake drum 1 rotates in the direction of the arrow 21 so that the brake shoe II is what is commonly referred to as the forward whereas the brake shoe I2 is what is comshoe,

It is well monly known as the trailing shoe.

, known that where equal pressures are applied socket formed in the rear sidefof the piston I6 for' forming a separable connection therewith and has the other end thereof pivoted to the upper end of the lever 2@ by a pin 3l, or any other suitable connection.

At the point where the lever 28 contacts the beveled 7end 26 of the brake shoe il, the lever is provided with a boss 33 which, in the present embodiment, is located midway between the pins 29 and 3l so that twice as much force is exerted on the brake shoe i i as on the brake shoe l2.

A retractile spring l34 is 'provided for moving the brake shoes into inactive position. The retractile movement 'of the brake shoes is limited n by shoulders 35 externally :formed on annuli 3G in which the piston rods are secured and which annuli are slidable within the cylinder bore M. One end of the retractile spring 34 is connected to a link 3l which in turn is connected to the brake shoe il. Under some conditions it is found desirable to have this link rest against the side of and form a guide for the lever 2B to prevent vibration and rattling thereof.

The retraetile spring 3@ must be of a strength sumcient to return the brake shoes to inactive position and also to retract the pistons l5 and it with sumcient force to drive the uid from the cylinder it! back through the conduits and past the return valve which is commonly assoelated with the discharge end of the'iuid compressor. Such a return valve is indicated by reference numeral 26 in Loughead Patent No. 1,847,402, dated March 1, l932.

While I have shown my. invention as applied to a hydraulic braking system, it is apparent that it may equally well be applied to mechanical or other type of braking system.

Having thus described my invention I wish it to be understood that it is capable of being incorporated in various forms and that the scope of my invention is following claims.

I claim:

l. T.n braking mechanism of the class described,l the combination of a rotatable member, a forward brake shoe, a reverse brake shoe, pivots' for said, shoes, means for actuating said shoes, said means being directly connected to toJ be 4limited solely ,by .the

said reverse shoe, a klever interposed betweenv said means and said forward shoe to multiply the force applied by said means to said forward shoe, and guide means for said lever carried by said forward shoe.

2. In braking apparatus of the class described,

the combination of a rotatable member, forward and reverse shoes adapted to be moved into engagement with said member, means for moving said shoes into engagement with said member, said means being directly connected to one of said shoes, force multiplying means interposed between said last-named means and said forward shoe, a guide for said force multiplying means carried by said forward shoe, and retracftile means for said shoes connected to said guide.

3. Inbraking apparauts of the class described, the combination of a rotatable member, forward and reverse shoes adapted to be brought into engagement therewith, means for applying said shoes, said means being directly connected to said reverse shoe, a non-yielding force multiplying connection between said applying means and said forward shoe, and a single spring connected to said shoes for moving the same away from said rotatable member.

4. In braking apparatus of the class described, the combination of a rotatable member, a forward shoe, a reverse shoe, applying means, said applying means being directly connected to said reverse shoe, non-yielding force multiplying connection between said applying means and said f forward shoe, and returns means for said shoes.

5. In braking apparatus of the class described, the combination of a rotatable member, a forward shoe, a reverse shoe, a double-ended hydraulic cylinder, a piston in one end of said cylinder directly connected to said reverse shoe, a vforce multiplying lever associated with said forward shoe, a piston in the other end of said cylinder connected to said' lever, said cylinder adapted to provide the increased travel necessitated by said lever, and spring means for moving said shoes out of engagement with said rotatable member.

WALLACE F. OLIVER. 

